drivers/s390/cio/ccwgroup.c

   1 /*
   2  *  bus driver for ccwgroup
   3  *
   4  *  Copyright IBM Corp. 2002, 2012
   5  *
   6  *  Author(s): Arnd Bergmann (arndb@de.ibm.com)
   7  *             Cornelia Huck (cornelia.huck@de.ibm.com)
   8  */
   9 #include <linux/module.h>
  10 #include <linux/errno.h>
  11 #include <linux/slab.h>
  12 #include <linux/list.h>
  13 #include <linux/device.h>
  14 #include <linux/init.h>
  15 #include <linux/ctype.h>
  16 #include <linux/dcache.h>
  17
  18 #include <asm/cio.h>
  19 #include <asm/ccwdev.h>
  20 #include <asm/ccwgroup.h>
  21
  22 #include "device.h"
  23
  24 #define CCW_BUS_ID_SIZE         10
  25
  26 /* In Linux 2.4, we had a channel device layer called "chandev"
  27  * that did all sorts of obscure stuff for networking devices.
  28  * This is another driver that serves as a replacement for just
  29  * one of its functions, namely the translation of single subchannels
  30  * to devices that use multiple subchannels.
  31  */
  32
  33 static struct bus_type ccwgroup_bus_type;
  34
  35 static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
  36 {
  37         int i;
  38         char str[8];
  39
  40         for (i = 0; i < gdev->count; i++) {
  41                 sprintf(str, "cdev%d", i);
  42                 sysfs_remove_link(&gdev->dev.kobj, str);
  43                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
  44         }
  45 }
  46
  47 /*
  48  * Remove references from ccw devices to ccw group device and from
  49  * ccw group device to ccw devices.
  50  */
  51 static void __ccwgroup_remove_cdev_refs(struct ccwgroup_device *gdev)
  52 {
  53         struct ccw_device *cdev;
  54         int i;
  55
  56         for (i = 0; i < gdev->count; i++) {
  57                 cdev = gdev->cdev[i];
  58                 if (!cdev)
  59                         continue;
  60                 spin_lock_irq(cdev->ccwlock);
  61                 dev_set_drvdata(&cdev->dev, NULL);
  62                 spin_unlock_irq(cdev->ccwlock);
  63                 gdev->cdev[i] = NULL;
  64                 put_device(&cdev->dev);
  65         }
  66 }
  67
  68 /**
  69  * ccwgroup_set_online() - enable a ccwgroup device
  70  * @gdev: target ccwgroup device
  71  *
  72  * This function attempts to put the ccwgroup device into the online state.
  73  * Returns:
  74  *  %0 on success and a negative error value on failure.
  75  */
  76 int ccwgroup_set_online(struct ccwgroup_device *gdev)
  77 {
  78         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
  79         int ret = -EINVAL;
  80
  81         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
  82                 return -EAGAIN;
  83         if (gdev->state == CCWGROUP_ONLINE)
  84                 goto out;
  85         if (gdrv->set_online)
  86                 ret = gdrv->set_online(gdev);
  87         if (ret)
  88                 goto out;
  89
  90         gdev->state = CCWGROUP_ONLINE;
  91 out:
  92         atomic_set(&gdev->onoff, 0);
  93         return ret;
  94 }
  95 EXPORT_SYMBOL(ccwgroup_set_online);
  96
  97 /**
  98  * ccwgroup_set_offline() - disable a ccwgroup device
  99  * @gdev: target ccwgroup device
 100  *
 101  * This function attempts to put the ccwgroup device into the offline state.
 102  * Returns:
 103  *  %0 on success and a negative error value on failure.
 104  */
 105 int ccwgroup_set_offline(struct ccwgroup_device *gdev)
 106 {
 107         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 108         int ret = -EINVAL;
 109
 110         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 111                 return -EAGAIN;
 112         if (gdev->state == CCWGROUP_OFFLINE)
 113                 goto out;
 114         if (gdrv->set_offline)
 115                 ret = gdrv->set_offline(gdev);
 116         if (ret)
 117                 goto out;
 118
 119         gdev->state = CCWGROUP_OFFLINE;
 120 out:
 121         atomic_set(&gdev->onoff, 0);
 122         return ret;
 123 }
 124 EXPORT_SYMBOL(ccwgroup_set_offline);
 125
 126 static ssize_t ccwgroup_online_store(struct device *dev,
 127                                      struct device_attribute *attr,
 128                                      const char *buf, size_t count)
 129 {
 130         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 131         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 132         unsigned long value;
 133         int ret;
 134
 135         if (!dev->driver)
 136                 return -EINVAL;
 137         if (!try_module_get(gdrv->driver.owner))
 138                 return -EINVAL;
 139
 140         ret = kstrtoul(buf, 0, &value);
 141         if (ret)
 142                 goto out;
 143
 144         if (value == 1)
 145                 ret = ccwgroup_set_online(gdev);
 146         else if (value == 0)
 147                 ret = ccwgroup_set_offline(gdev);
 148         else
 149                 ret = -EINVAL;
 150 out:
 151         module_put(gdrv->driver.owner);
 152         return (ret == 0) ? count : ret;
 153 }
 154
 155 static ssize_t ccwgroup_online_show(struct device *dev,
 156                                     struct device_attribute *attr,
 157                                     char *buf)
 158 {
 159         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 160         int online;
 161
 162         online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0;
 163
 164         return scnprintf(buf, PAGE_SIZE, "%d\n", online);
 165 }
 166
 167 /*
 168  * Provide an 'ungroup' attribute so the user can remove group devices no
 169  * longer needed or accidentially created. Saves memory :)
 170  */
 171 static void ccwgroup_ungroup_callback(struct device *dev)
 172 {
 173         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 174
 175         mutex_lock(&gdev->reg_mutex);
 176         if (device_is_registered(&gdev->dev)) {
 177                 __ccwgroup_remove_symlinks(gdev);
 178                 device_unregister(dev);
 179                 __ccwgroup_remove_cdev_refs(gdev);
 180         }
 181         mutex_unlock(&gdev->reg_mutex);
 182 }
 183
 184 static ssize_t ccwgroup_ungroup_store(struct device *dev,
 185                                       struct device_attribute *attr,
 186                                       const char *buf, size_t count)
 187 {
 188         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 189         int rc;
 190
 191         /* Prevent concurrent online/offline processing and ungrouping. */
 192         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 193                 return -EAGAIN;
 194         if (gdev->state != CCWGROUP_OFFLINE) {
 195                 rc = -EINVAL;
 196                 goto out;
 197         }
 198         /* Note that we cannot unregister the device from one of its
 199          * attribute methods, so we have to use this roundabout approach.
 200          */
 201         rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
 202 out:
 203         if (rc) {
 204                 if (rc != -EAGAIN)
 205                         /* Release onoff "lock" when ungrouping failed. */
 206                         atomic_set(&gdev->onoff, 0);
 207                 return rc;
 208         }
 209         return count;
 210 }
 211 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 212 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 213
 214 static struct attribute *ccwgroup_attrs[] = {
 215         &dev_attr_online.attr,
 216         &dev_attr_ungroup.attr,
 217         NULL,
 218 };
 219 static struct attribute_group ccwgroup_attr_group = {
 220         .attrs = ccwgroup_attrs,
 221 };
 222 static const struct attribute_group *ccwgroup_attr_groups[] = {
 223         &ccwgroup_attr_group,
 224         NULL,
 225 };
 226
 227 static void ccwgroup_release(struct device *dev)
 228 {
 229         kfree(to_ccwgroupdev(dev));
 230 }
 231
 232 static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 233 {
 234         char str[8];
 235         int i, rc;
 236
 237         for (i = 0; i < gdev->count; i++) {
 238                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj,
 239                                        &gdev->dev.kobj, "group_device");
 240                 if (rc) {
 241                         for (--i; i >= 0; i--)
 242                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 243                                                   "group_device");
 244                         return rc;
 245                 }
 246         }
 247         for (i = 0; i < gdev->count; i++) {
 248                 sprintf(str, "cdev%d", i);
 249                 rc = sysfs_create_link(&gdev->dev.kobj,
 250                                        &gdev->cdev[i]->dev.kobj, str);
 251                 if (rc) {
 252                         for (--i; i >= 0; i--) {
 253                                 sprintf(str, "cdev%d", i);
 254                                 sysfs_remove_link(&gdev->dev.kobj, str);
 255                         }
 256                         for (i = 0; i < gdev->count; i++)
 257                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 258                                                   "group_device");
 259                         return rc;
 260                 }
 261         }
 262         return 0;
 263 }
 264
 265 static int __get_next_id(const char **buf, struct ccw_dev_id *id)
 266 {
 267         unsigned int cssid, ssid, devno;
 268         int ret = 0, len;
 269         char *start, *end;
 270
 271         start = (char *)*buf;
 272         end = strchr(start, ',');
 273         if (!end) {
 274                 /* Last entry. Strip trailing newline, if applicable. */
 275                 end = strchr(start, '\n');
 276                 if (end)
 277                         *end = '\0';
 278                 len = strlen(start) + 1;
 279         } else {
 280                 len = end - start + 1;
 281                 end++;
 282         }
 283         if (len <= CCW_BUS_ID_SIZE) {
 284                 if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3)
 285                         ret = -EINVAL;
 286         } else
 287                 ret = -EINVAL;
 288
 289         if (!ret) {
 290                 id->ssid = ssid;
 291                 id->devno = devno;
 292         }
 293         *buf = end;
 294         return ret;
 295 }
 296
 297 /**
 298  * ccwgroup_create_dev() - create and register a ccw group device
 299  * @parent: parent device for the new device
 300  * @gdrv: driver for the new group device
 301  * @num_devices: number of slave devices
 302  * @buf: buffer containing comma separated bus ids of slave devices
 303  *
 304  * Create and register a new ccw group device as a child of @parent. Slave
 305  * devices are obtained from the list of bus ids given in @buf.
 306  * Returns:
 307  *  %0 on success and an error code on failure.
 308  * Context:
 309  *  non-atomic
 310  */
 311 int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
 312                         int num_devices, const char *buf)
 313 {
 314         struct ccwgroup_device *gdev;
 315         struct ccw_dev_id dev_id;
 316         int rc, i;
 317
 318         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
 319                        GFP_KERNEL);
 320         if (!gdev)
 321                 return -ENOMEM;
 322
 323         atomic_set(&gdev->onoff, 0);
 324         mutex_init(&gdev->reg_mutex);
 325         mutex_lock(&gdev->reg_mutex);
 326         gdev->count = num_devices;
 327         gdev->dev.bus = &ccwgroup_bus_type;
 328         gdev->dev.parent = parent;
 329         gdev->dev.release = ccwgroup_release;
 330         device_initialize(&gdev->dev);
 331
 332         for (i = 0; i < num_devices && buf; i++) {
 333                 rc = __get_next_id(&buf, &dev_id);
 334                 if (rc != 0)
 335                         goto error;
 336                 gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id);
 337                 /*
 338                  * All devices have to be of the same type in
 339                  * order to be grouped.
 340                  */
 341                 if (!gdev->cdev[i] || !gdev->cdev[i]->drv ||
 342                     gdev->cdev[i]->drv != gdev->cdev[0]->drv ||
 343                     gdev->cdev[i]->id.driver_info !=
 344                     gdev->cdev[0]->id.driver_info) {
 345                         rc = -EINVAL;
 346                         goto error;
 347                 }
 348                 /* Don't allow a device to belong to more than one group. */
 349                 spin_lock_irq(gdev->cdev[i]->ccwlock);
 350                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 351                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 352                         rc = -EINVAL;
 353                         goto error;
 354                 }
 355                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 356                 spin_unlock_irq(gdev->cdev[i]->ccwlock);
 357         }
 358         /* Check for sufficient number of bus ids. */
 359         if (i < num_devices) {
 360                 rc = -EINVAL;
 361                 goto error;
 362         }
 363         /* Check for trailing stuff. */
 364         if (i == num_devices && strlen(buf) > 0) {
 365                 rc = -EINVAL;
 366                 goto error;
 367         }
 368
 369         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 370         gdev->dev.groups = ccwgroup_attr_groups;
 371
 372         if (gdrv) {
 373                 gdev->dev.driver = &gdrv->driver;
 374                 rc = gdrv->setup ? gdrv->setup(gdev) : 0;
 375                 if (rc)
 376                         goto error;
 377         }
 378         rc = device_add(&gdev->dev);
 379         if (rc)
 380                 goto error;
 381         rc = __ccwgroup_create_symlinks(gdev);
 382         if (rc) {
 383                 device_del(&gdev->dev);
 384                 goto error;
 385         }
 386         mutex_unlock(&gdev->reg_mutex);
 387         return 0;
 388 error:
 389         for (i = 0; i < num_devices; i++)
 390                 if (gdev->cdev[i]) {
 391                         spin_lock_irq(gdev->cdev[i]->ccwlock);
 392                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 393                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 394                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 395                         put_device(&gdev->cdev[i]->dev);
 396                         gdev->cdev[i] = NULL;
 397                 }
 398         mutex_unlock(&gdev->reg_mutex);
 399         put_device(&gdev->dev);
 400         return rc;
 401 }
 402 EXPORT_SYMBOL(ccwgroup_create_dev);
 403
 404 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
 405                              void *data)
 406 {
 407         struct device *dev = data;
 408
 409         if (action == BUS_NOTIFY_UNBIND_DRIVER)
 410                 device_schedule_callback(dev, ccwgroup_ungroup_callback);
 411
 412         return NOTIFY_OK;
 413 }
 414
 415 static struct notifier_block ccwgroup_nb = {
 416         .notifier_call = ccwgroup_notifier
 417 };
 418
 419 static int __init init_ccwgroup(void)
 420 {
 421         int ret;
 422
 423         ret = bus_register(&ccwgroup_bus_type);
 424         if (ret)
 425                 return ret;
 426
 427         ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 428         if (ret)
 429                 bus_unregister(&ccwgroup_bus_type);
 430
 431         return ret;
 432 }
 433
 434 static void __exit cleanup_ccwgroup(void)
 435 {
 436         bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 437         bus_unregister(&ccwgroup_bus_type);
 438 }
 439
 440 module_init(init_ccwgroup);
 441 module_exit(cleanup_ccwgroup);
 442
 443 /************************** driver stuff ******************************/
 444
 445 static int ccwgroup_remove(struct device *dev)
 446 {
 447         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 448         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 449
 450         if (!dev->driver)
 451                 return 0;
 452         if (gdrv->remove)
 453                 gdrv->remove(gdev);
 454
 455         return 0;
 456 }
 457
 458 static void ccwgroup_shutdown(struct device *dev)
 459 {
 460         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 461         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 462
 463         if (!dev->driver)
 464                 return;
 465         if (gdrv->shutdown)
 466                 gdrv->shutdown(gdev);
 467 }
 468
 469 static int ccwgroup_pm_prepare(struct device *dev)
 470 {
 471         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 472         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 473
 474         /* Fail while device is being set online/offline. */
 475         if (atomic_read(&gdev->onoff))
 476                 return -EAGAIN;
 477
 478         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 479                 return 0;
 480
 481         return gdrv->prepare ? gdrv->prepare(gdev) : 0;
 482 }
 483
 484 static void ccwgroup_pm_complete(struct device *dev)
 485 {
 486         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 487         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 488
 489         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 490                 return;
 491
 492         if (gdrv->complete)
 493                 gdrv->complete(gdev);
 494 }
 495
 496 static int ccwgroup_pm_freeze(struct device *dev)
 497 {
 498         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 499         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 500
 501         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 502                 return 0;
 503
 504         return gdrv->freeze ? gdrv->freeze(gdev) : 0;
 505 }
 506
 507 static int ccwgroup_pm_thaw(struct device *dev)
 508 {
 509         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 510         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 511
 512         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 513                 return 0;
 514
 515         return gdrv->thaw ? gdrv->thaw(gdev) : 0;
 516 }
 517
 518 static int ccwgroup_pm_restore(struct device *dev)
 519 {
 520         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 521         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 522
 523         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 524                 return 0;
 525
 526         return gdrv->restore ? gdrv->restore(gdev) : 0;
 527 }
 528
 529 static const struct dev_pm_ops ccwgroup_pm_ops = {
 530         .prepare = ccwgroup_pm_prepare,
 531         .complete = ccwgroup_pm_complete,
 532         .freeze = ccwgroup_pm_freeze,
 533         .thaw = ccwgroup_pm_thaw,
 534         .restore = ccwgroup_pm_restore,
 535 };
 536
 537 static struct bus_type ccwgroup_bus_type = {
 538         .name   = "ccwgroup",
 539         .remove = ccwgroup_remove,
 540         .shutdown = ccwgroup_shutdown,
 541         .pm = &ccwgroup_pm_ops,
 542 };
 543
 544 /**
 545  * ccwgroup_driver_register() - register a ccw group driver
 546  * @cdriver: driver to be registered
 547  *
 548  * This function is mainly a wrapper around driver_register().
 549  */
 550 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 551 {
 552         /* register our new driver with the core */
 553         cdriver->driver.bus = &ccwgroup_bus_type;
 554
 555         return driver_register(&cdriver->driver);
 556 }
 557 EXPORT_SYMBOL(ccwgroup_driver_register);
 558
 559 static int __ccwgroup_match_all(struct device *dev, void *data)
 560 {
 561         return 1;
 562 }
 563
 564 /**
 565  * ccwgroup_driver_unregister() - deregister a ccw group driver
 566  * @cdriver: driver to be deregistered
 567  *
 568  * This function is mainly a wrapper around driver_unregister().
 569  */
 570 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 571 {
 572         struct device *dev;
 573
 574         /* We don't want ccwgroup devices to live longer than their driver. */
 575         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 576                                          __ccwgroup_match_all))) {
 577                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 578
 579                 mutex_lock(&gdev->reg_mutex);
 580                 __ccwgroup_remove_symlinks(gdev);
 581                 device_unregister(dev);
 582                 __ccwgroup_remove_cdev_refs(gdev);
 583                 mutex_unlock(&gdev->reg_mutex);
 584                 put_device(dev);
 585         }
 586         driver_unregister(&cdriver->driver);
 587 }
 588 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 589
 590 /**
 591  * ccwgroup_probe_ccwdev() - probe function for slave devices
 592  * @cdev: ccw device to be probed
 593  *
 594  * This is a dummy probe function for ccw devices that are slave devices in
 595  * a ccw group device.
 596  * Returns:
 597  *  always %0
 598  */
 599 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 600 {
 601         return 0;
 602 }
 603 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 604
 605 /**
 606  * ccwgroup_remove_ccwdev() - remove function for slave devices
 607  * @cdev: ccw device to be removed
 608  *
 609  * This is a remove function for ccw devices that are slave devices in a ccw
 610  * group device. It sets the ccw device offline and also deregisters the
 611  * embedding ccw group device.
 612  */
 613 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 614 {
 615         struct ccwgroup_device *gdev;
 616
 617         /* Ignore offlining errors, device is gone anyway. */
 618         ccw_device_set_offline(cdev);
 619         /* If one of its devices is gone, the whole group is done for. */
 620         spin_lock_irq(cdev->ccwlock);
 621         gdev = dev_get_drvdata(&cdev->dev);
 622         if (!gdev) {
 623                 spin_unlock_irq(cdev->ccwlock);
 624                 return;
 625         }
 626         /* Get ccwgroup device reference for local processing. */
 627         get_device(&gdev->dev);
 628         spin_unlock_irq(cdev->ccwlock);
 629         /* Unregister group device. */
 630         mutex_lock(&gdev->reg_mutex);
 631         if (device_is_registered(&gdev->dev)) {
 632                 __ccwgroup_remove_symlinks(gdev);
 633                 device_unregister(&gdev->dev);
 634                 __ccwgroup_remove_cdev_refs(gdev);
 635         }
 636         mutex_unlock(&gdev->reg_mutex);
 637         /* Release ccwgroup device reference for local processing. */
 638         put_device(&gdev->dev);
 639 }
 640 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
 641 MODULE_LICENSE("GPL");